Iterative Impulsive Noise Mitigation and Channel Equalization Design for Wavelet-OFDM PLC Receivers

The multipath effect and impulsive noise (IN) of a power-line channel may affect the performance of power-line communications. Specifically, these two impairments reduce the accuracy of the channel estimation and increase the bit error rate (BER). In this thesis, we focus on the Discrete Wavelet Transform based orthogonal frequency division multiplexing (Wavelet-based OFDM) receiver, which is defined in IEEE P1901 standard, and propose an iterative receiver architecture. Moreover, we devise an associated iterative channel estimation and IN cancellation algorithm for this receiver. Due to IN, the conventional channel estimation algorithm may diverge or a poor estimated channel response. Therefore, an accurate channel estimation becomes more challenging. In our proposed iterative receiver, the resulting performance heavily depends on the quality of the channel estimation. We apply a variable step-size affine projection algorithm (VSS-APA) to estimate the channel response while avoiding the affect of IN. Before the DWT operation, we pre-mitigate the IN by a blanking device to cancel the strong part of the IN sources. On the other hand, after the DWT operation, we iteratively post-mitigate the residual IN. The post-IN mitigation block iteratively cancel the residual IN and update the estimated channel impulse response, so that the channel estimation and IN mitigation are in a mutually beneficial status. Simulation results show that the proposed iterative receiver not only increases the accuracy of the channel estimator, but also effectively cancel IN sources.